static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
{
struct ipcomp_data *ipcd = x->data;
const int plen = skb->len;
int dlen = IPCOMP_SCRATCH_SIZE;
const u8 *start = skb->data;
const int cpu = get_cpu();
u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu);
int err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
int len;
if (err)
goto out;
if (dlen < (plen + sizeof(struct ip_comp_hdr))) {
err = -EINVAL;
goto out;
}
len = dlen - plen;
if (len > skb_tailroom(skb))
len = skb_tailroom(skb);
__skb_put(skb, len);
len += plen;
skb_copy_to_linear_data(skb, scratch, len);
while ((scratch += len, dlen -= len) > 0) {
skb_frag_t *frag;
struct page *page;
err = -EMSGSIZE;
if (WARN_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS))
goto out;
frag = skb_shinfo(skb)->frags + skb_shinfo(skb)->nr_frags;
page = alloc_page(GFP_ATOMIC);
err = -ENOMEM;
if (!page)
goto out;
__skb_frag_set_page(frag, page);
len = PAGE_SIZE;
if (dlen < len)
len = dlen;
frag->page_offset = 0;
skb_frag_size_set(frag, len);
memcpy(skb_frag_address(frag), scratch, len);
skb->truesize += len;
skb->data_len += len;
skb->len += len;
skb_shinfo(skb)->nr_frags++;
}
err = 0;
out:
put_cpu();
return err;
}
/* Consolidate skb with a frag_list into a brand new one with local pages on
* frags. Returns 0 or -ENOMEM if can't allocate new pages.
*/
static int xenvif_handle_frag_list(struct xenvif *vif, struct sk_buff *skb)
{
unsigned int offset = skb_headlen(skb);
skb_frag_t frags[MAX_SKB_FRAGS];
int i;
struct ubuf_info *uarg;
struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
vif->tx_zerocopy_sent += 2;
vif->tx_frag_overflow++;
xenvif_fill_frags(vif, nskb);
/* Subtract frags size, we will correct it later */
skb->truesize -= skb->data_len;
skb->len += nskb->len;
skb->data_len += nskb->len;
/* create a brand new frags array and coalesce there */
for (i = 0; offset < skb->len; i++) {
struct page *page;
unsigned int len;
BUG_ON(i >= MAX_SKB_FRAGS);
page = alloc_page(GFP_ATOMIC|__GFP_COLD);
if (!page) {
int j;
skb->truesize += skb->data_len;
for (j = 0; j < i; j++)
put_page(frags[j].page.p);
return -ENOMEM;
}
if (offset + PAGE_SIZE < skb->len)
len = PAGE_SIZE;
else
len = skb->len - offset;
if (skb_copy_bits(skb, offset, page_address(page), len))
BUG();
offset += len;
frags[i].page.p = page;
frags[i].page_offset = 0;
skb_frag_size_set(&frags[i], len);
}
/* swap out with old one */
memcpy(skb_shinfo(skb)->frags,
frags,
i * sizeof(skb_frag_t));
skb_shinfo(skb)->nr_frags = i;
skb->truesize += i * PAGE_SIZE;
/* remove traces of mapped pages and frag_list */
skb_frag_list_init(skb);
uarg = skb_shinfo(skb)->destructor_arg;
uarg->callback(uarg, true);
skb_shinfo(skb)->destructor_arg = NULL;
skb_shinfo(nskb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
kfree_skb(nskb);
return 0;
}
